1. Module 8

1.14. Page 3

Lesson 3

Module 8—Acid-Base Equilibrium

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The proton transfer reaction during acid-base reactions, as described by the Brønsted-Lowry concept, is unique. For instance, the reaction of ammonia, NH3(aq), produces the ammonium ion, NH4+(aq). Note that the difference between these two chemical formulas is one proton. More interesting is that it is foreseeable that the product could easily donate a proton in a future reaction, thus acting as a Brønsted-Lowry acid.

 

Read “Conjugate Acids and Bases” on pages 724–726 in the textbook to learn more about acid-base pairs.

 

Self-Check

 

SC 2. Complete “Practice” questions 7–8 on page 726 of the textbook.

 

Check your work.
Self-Check Answers

 

Contact your teacher if your answers vary significantly from the answers provided here.

 

SC 2.

 

Practice 7.

  1. HCO3–(aq), CO32–(aq) and S2–(aq), HS–(aq)
  2. H2CO3(aq), HCO3–(aq) and OH–(aq), H2O(l)
  3. HSO4–(aq), SO42–(aq) and HPO42–(aq), H2PO4–(aq)
  4. H2O(l), H3O+(aq) and H2O(l), OH–(aq)

Practice 8.

 

HCO3–(aq), CO32–(aq) and H2CO3(aq), HCO3–(aq)

 

try this Try This

 

In the previous section you learned about the proton transfer concept. In this activity you will further test this theory by applying material learned in this and previous lessons.

 

TR 1. The following acids are responsible for acid deposition. Can their acidity be explained using the proton transfer concept?

  1. HNO3(aq)
  2. HNO2(aq)
  3. H2SO4(aq)
  4. H2SO3(aq)

TR 2. Carbonate ions, CO32–, from limestone, the mineral calcium carbonate, are a component of soils in Alberta. Soils in Alberta tend to be alkaline, as does the pH of the water in most Alberta lakes. Is it possible that the observed pH of soil and lake water could be due to the presence of carbonate in soil?

 

TR 3. Acid deposition has had relatively little effect on the pH of soils in most parts of Alberta. Use a chemical reaction to explain this observation. In the reaction you write, identify the conjugate acid-base pairs.

 

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